Topography correction for testing of redundant array elements

Abstract

A data topography correction circuit for a semiconductor memory device and method for testing the device is provided. The data topography correction circuit includes a redundant hit circuit for determining if a redundant element has been used to replace a defective element; and a redundant topology correction scrambler circuit for converting data from a data topology of the defective element to a data topology of the redundant element. The method includes the steps of providing an address of a memory array element of the device to be tested; determining if the memory array element has been replaced with a redundant element; and, if the memory array element has been replaced, correcting test data to the data topology of the redundant element.

What is claimed is:  
     
       1. A data topography correction circuit for a semiconductor memory device comprising: 
       a redundant hit circuit for determining if a redundant element has been used to replace a defective element of the semiconductor memory device; and  
       a redundant topology correction scrambler circuit for converting data from a data topology of the defective element to a data topology of the redundant element.  
     
     
       2. The data topography correction circuit as in  claim 1 , wherein the redundant hit circuit is adapted to compare a memory element address to repair fuse information to determine if addressed memory element has been replaced with a redundant element. 
     
     
       3. The data topography correction circuit as in  claim 1 , wherein the redundant topology correction scrambler circuit is adapted to determine if the data topology of the redundant element is the same as the data topology of the defective element, wherein if the data topologies are the same, the redundant topology correction scrambler circuit allows incoming data to pass through. 
     
     
       4. The data topography correction circuit as in  claim 3 , wherein if the data topologies are different, the redundant topology correction scrambler circuit determines the data topology of the redundant element. 
     
     
       5. The data topography correction circuit as in  claim 1 , further comprising a multiplexer for multiplexing corrected data with raw data to a memory array of the semiconductor memory device upon a write operation. 
     
     
       6. The data topography correction circuit as in  claim 1 , further comprising a multiplexer for multiplexing corrected data with raw data to an off-chip driver from the semiconductor memory device upon a read operation. 
     
     
       7. The data topography correction circuit as in  claim 1 , further comprising 
       a first multiplexer for multiplexing corrected data with raw data to a memory array of the semiconductor memory device upon a write operation; and  
       a second multiplexer for multiplexing corrected data with raw data to an off-chip driver from the semiconductor memory device upon a read operation.  
     
     
       8. A semiconductor memory device comprising: 
       a memory cell array including a plurality of memory elements and a plurality of redundant memory elements; and  
       a data topography correction circuit including:  
       a redundant hit circuit for determining if a redundant memory element has been used to replace a defective memory element of the semiconductor memory device; and  
       a redundant topology correction scrambler circuit for converting data from a data topology of the defective memory element to a data topology of the redundant memory element.  
     
     
       9. The semiconductor memory device as in  claim 8 , wherein the redundant hit circuit is adapted to compare a memory element address to repair fuse information to determine if addressed memory element has been replaced with a redundant memory element. 
     
     
       10. The semiconductor memory device as in  claim 8 , wherein the redundant topology correction scrambler circuit is adapted to determine if the data topology of the redundant memory element is the same as the data topology of the defective memory element, wherein if the data topologies are the same, the redundant topology correction scrambler circuit allows incoming data to pass through. 
     
     
       11. The semiconductor memory device as in  claim 10 , wherein if the data topologies are different, the redundant topology correction scrambler circuit determines the data topology of the redundant memory element. 
     
     
       12. The semiconductor memory device as in  claim 8 , further comprising a multiplexer for multiplexing corrected data with raw data to a memory array of the semiconductor memory device upon a write operation. 
     
     
       13. The semiconductor memory device as in  claim 8 , further comprising a multiplexer for multiplexing corrected data with raw data to an off-chip driver from the semiconductor memory device upon a read operation. 
     
     
       14. The semiconductor memory device as in  claim 8 , further comprising 
       a first multiplexer for multiplexing corrected data with raw data to a memory array of the semiconductor memory device upon a write operation; and  
       a second multiplexer for multiplexing corrected data with raw data to an off-chip driver from the semiconductor memory device upon a read operation.  
     
     
       15. A method for testing a semiconductor memory device, the method comprising the steps of: 
       applying a test mode signal to place the semiconductor memory device in a test mode;  
       providing an address of a memory array element of the semiconductor memory device to be tested;  
       determining if the memory array element has been replaced with a redundant element; and  
       if the memory array element has been replaced, correcting test data to a data topology of the redundant element.  
     
     
       16. The method as in  claim 15  wherein said test mode is a pre-fuse test mode, the method further comprising the steps of: 
       determining if any memory array elements are defective; and  
       replacing defective memory array elements with redundant elements.  
     
     
       17. The method as in  claim 15 , wherein the determining if the memory array element has been replaced with a redundant element step further comprises the step of comparing the address of the memory array to repair fuse information. 
     
     
       18. The method as in  claim 15 , further comprising the step of, if the memory array element has been replaced, determining if the redundant element has a same data topology as the memory array element. 
     
     
       19. The method as in  claim 15 , wherein the providing an address of a memory array element of the semiconductor memory device to be tested is performed during a write operation. 
     
     
       20. The method as in  claim 15 , wherein the providing an address of a memory array element of the semiconductor memory device to be tested is performed during a read operation.